Eat whole fruits (especially blueberries) and you'll have as much as 23% lower risk of
developing type 2 diabetes, and drink fruit juice and you'll have 21% higher risk!, according to this Harvard Gazette article. The research article is on BMJ. A possible explanation for this difference is presence of fiber in whole fruits (and lack of it in juice), which slows down sugar intake. If that's true, I believe drinking fruit juice with a meal, bread, vegetables or anything that can slow down sugar intake may reduce the negative effect of its high glacemic index.
Another interesting point to note is that not all fruits are created equal in lowering or raising type 2 diabetes risk. The graph in the middle of the BMJ article (the second link above) shows that blueberries offer the greatest advantage and cantaloupes go the opposite direction (raising the risk). Of course it doesn't mean we should generall avoid cantaloupes because all fruits have their nutritional value.
